Process of and apparatus for the manufacture of paper and the like



E. HUTCHINS Dec. 14, 1937.

PROCESS OF AND APPARATUS FOR THE MANUFACTURE OF PAPER AND THE LIKE FiledFeb.- 19, 1935 ATTORN EY Patented Dec. 14, 1937 PATENT OFFICE PROCESS OFAND APPARATUS FOR THE MANUFACTURE OF PAPER AND THELIKE Edward Hutchins,Glens Falls, N. Y., assignor to International Paper Company, acorporation of New York Application February 19, 1935, Serial No. 7,163

4 Claims.

This invention relates to improvements in the manufacture of paper andlike products, and,

more particularly to an improved method of and apparatus for forming aweb of fibrous material so that the said fibers are thoroughlyinterlaced and evenly distributed throughout the said web.

In the manufacture of paper on a paper machine of the Fourdrinier type,a suitably'prepared fibrous stock 01' the desired consistency isdeposited on an endless travelling screen or wire through which water inthe stock is drained leaving the fibers shortly after the deposition ofthe stock on the screen or wire in'the form of a web. To assist in thedrainage of the water through the screen or wire various mechanisms suchas tableor tube rolls, suction boxes and the like, are normallyemployed. 'As the water is drained from the stock the fibres thereofgradually settle into web form so that there-is a building up-oi the webto the desired thickness as the screen or wire travels over the table ortube rolls, suction devices, etc. By the time the web reaches a the lastsuction box substantially all of the fibres have settled into web form.At the beginning of the settling of the fibres into web form 1 havefound that the stock comprises essentially two parts, a layer of settledfibres adjacent the screen or wire and a layer of unsettled fibressupported by the first layer. As more and more of the fibres becomesettled into web form the thickness 01' the unsettled layer graduallydiminishes.

I have also found that the iormation of a poorly formed sheet or web isdue, other conditions being the same, primarily to the fact that thefibres are improperly felted'or interlaced and distributed in the sheetso that when the sheet is held in the light, cloths oi fibres, appearingas darkened or blotched areas, may be seen. Such formation is generallydesignated as a wild" sheet.

Accordingly, the primary object of my present invention resides in thedevelopment 01 a new method for controlling the formation of the web sothat the finished sheet will show the fibres thereof thoroughlyinterlaced and matted and uniformly distributed throughout. Anotherobject of my present invention resides inthe provision of mechanism forcarrying out the steps of the method.

sun another object of this invention resides in the provision ofagitating mechanism located above the paper making screen andpreferably, although not necessarily, completely immersed in the upperportion of the papermaking stock. The agitating device is so designed asto smooth on the upper surface of the fibrous layer which has alreadybeen formed and to agitate the fibres constituting the upper orunsettled layer of stock.

A further object of this invention resides in the provision of mechanismlocated above the paper making screen and mounted for reciprocationtransversely thereof. Preferably the device is at least partiallyimmersed in the paper making stock and is so designed as to smooth offthis upper surface of the stock which has settled on the screen and toagitate the unsettled stock.

These and other objects of this invention will become more apparent froma study of the following description taken with reference to theaccompanying drawing in which I Fig. 1 is an enlarged detailed sectionalview of so much of a Fourdrinier screen or wire as is necessary to aclear understanding of the principle of operation of the invention,

Fig. 2 is a top plan view of the agitating device, and

Fig. 3 is a sectional view along the lines 3-3 of Fig. 1 showing apreferred mechanism for operating the plate or agitating device. 1

Referring now to the drawing in which like numerals indicate like parts,and particularly to. Fig. 1 the numeral l0 represents the conventionalFourdrinier screen or wire which is, as is well known in the papermaking art, of the endless type .and travels from the breast roll to thecouch roll of the machine, the latter being connected to suitabledriving mechanism. The screen or wire is supported by table or tuberolls l l which serve to assist in draining water from the paper .makingstock leaving' the fibres thereof in the form of a web.

Assuming that the screen or wire is travelling in the directionindicated by the arrows and that the paper making stock has beendeposited thereon by means of any of the well known stock depositingdevices, it will be appreciated that those.

fibres adjacent the said screen or wire will form a layer or web I2 byvirtue of the drainage of water from the stock, which drainage commencesas soon as the stockis deposited.- Therewill also be a layer l3 ofunsettled stock from which the water has not been drained sufilcientlyto form a web. As the two layers of stock travel with the screen or wiremore and more water is drained from the unsettled layer therebygradually and progressively increasing the thickness of the settledlayer until the unsettled layer has gradually disappeared.

Due to the rapidity with which the water is drained from the stock thereis a tendency for the fibres to be unevenly distributed across thescreen or wire. Moreover, the travel of the latter tends to cause thefibres to be deposited in one direction and parallel to each other sothat the fibres will be insufficiently interlaced or matted. Althoughthis tendency varies to some extent depending upon the character of thestock used substantially all paper is stronger in the machine directionthan in a direction transverse thereto.

To overcome the defects I have provided an agitating device comprising aplate I extending across the paper making screen or wire and preferablycompletely immersed in the paper making stock. The plate'is secured ateach end to the end of a spring arm l5 which is anchored in thefoundation or fioor of the mill. Spring leaf means It are provided togive to the spring armli the necessary strength and flexibility. The

. plate is held by the spring arms under sufficient tension to preventany substantial degree of sag.

Reciprocatory or oscillatory motion is imparted to 'the spring arms bymeans of a yoke ll pivotally connected to an eccentric strap l8 mountedon ec-.-

centric i9 and drive (not shown) thru drive 20 .from a motor or othermechanism.

Preferably the stroke or reciprocation of the plate It is not over /2"and at a frequency? of from 600-3600 cycles a minute. The spring armsare designed so that their period of vibration is substantially equal tothe frequency used. In this manner undue strains on the drivingmechanism and mechanical parts are avoided and the power consumption isheld sufficiently low as to permit an economical operation of thedevice.

. The plate or agitator I2 is not of-uniform thickness, being thicker atthe breast or front end of the device and tapering toward the couch orrear thereof, as will be noted from an inspection of Fig. 1. The'frontend, although of substantial thickness, merges'intoa point. Thisconstruction in combination with the frequency of vibration employedprevents any tendency of the fibres to bunch or stick to the plate atthis point. The under surface of the plate or agitator is smooth andrests on the settled layer of stock and due to the fact that the platereciprocates across the said layer the top surface thereof is smoothedoif, thereby distributing the fibres evenly across the screen or wireand thoroughly and uniformly interlacing or matting them together.

The upper surface of the plate or agitator is provided with a pluralityof spaced ribs 22 which extend in a direction substantially transverseto the major axis thereof and parallel to the path of movement of thepaper making screen. As will'be appreciated these ribs serve to agitatethe unsettled layerof stock thereby assisting in distributing the fibresuniformly across the screen or wire and in interlacing or matting themto- .gether. Hence by the time this unsettled layer has passed over theagitator the 'fibres thereof, when deposited on the initially formedlayer, form a web, the fibres of which are uniformly distributedthroughout and evenly and thoroughly-. interlaced or felted. Theagitation of the fibres of the unsettled layer in a direction transverseto their normal movement also substantially prevents any tendency of thefibres to be deposited in one direction. Thus the finished sheet ofpaper will exhibit no marked variations in strength lengthwise andacross the said sheet.

While I have illustrated and described my invention with some degree ofparticularity, I realhe that in practice many alterations therein may bemade. I, therefore, reserve, the right and privilege of changing theform of details of construction or otherwise altering the arrangement ofthe correlated parts without departing from the spiritv of the inventionor the scope of the appended claims.

Having ,now described my invention as required by the patent statutes,what I desire to claim as new is:

1. In a process for the manufacture of paper wherein a fibrous stock isdeposited on a web forming device and subjected to drainage wherebygradually to build up a fibrous web of suitable thickness, the steps ofsmoothing over that layer of fibres which is initially formed into a webas water is withdrawn from the pulp suspension, and simultaneouslyagitating. the remainder of said stock in a direction transverse to themovement of said formed web and thereafter forming said stock with saidformed web into a unitary web of fibrous material.

2. In a device of the class described, a paper making screen on which asuitable paper making stock 'is deposited, means for agitating the.upper layer of said stock comprising a plate having an uneven uppersurface extending across said screen and immersed in said stock, andmeans to reciprocate said plate.

3. In a device of the class described a moving paper making screen onwhich a suitable paper making stock is deposited, means for agitatingthe upper layer of said stock and for smoothing off the fibres of saidstock which are initially deposited into web form comprising a plateimmersed in said stock and having a smooth under surface resting on saidweb and an uneven upper surface, and means for reciprocating said plate.

4. In a device of the class described, a moving paper making screen onwhich a suitable; paper making stock is deposited, means for agitatingthe upper layer of said stock and for smoothing off the fibres of saidstock which are initially EDWARD HUTCHI'NS.

